Polishing and buffing wheel



H. ZIMMERMAN POLISHING AND BUFFING WHE-EL June 30, 1953 2 Sheets-Sheet l Filed June 26, 1950 171:1 DB8. I'IGEI. [J5/D. :GII

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June 30, 1953 H.-z|MMERMAN POLISHING AND BUFFING WHEEL Filed June' 26. 195o 2 Sheets-Sheet 2 -Bale Patented June 30, 1953 Y UNITED STATES PATENT OFFICE 2,643,493 PoLIsHiNG AND BUFFING WHEEL Harry Zimmerman, Toronto, Ontario, Canada AppiicationfJune 26, 195o, serial No. 170,456

This invention relates to a bu'fling wheel and in particular to a method and means for forming a waved builing wheel having dense columns to support the pressure of the lathe clamps and a waved formation extending throughout the Width of the wheel.

Various methods for producing buiiing wheels having a waved periphery have been proposed such as preforming the individual wheel sections to the desired waved shape, or by inserting between the sections or groups of sections preformed spacers. Typical examples of these means for forming waved buing wheels are illustrated in U. S. Patents Nos. 2,044,858 and 2,187,602. The objection to both types of waved bufng wheels is that they are too compact between the lathe clamps and tend to produce a hard buing or polishing surface; theyv are not adaptable for re-arrangement to change the shape of the wave on theperiphery of the wheel.

An object of thi-s invention is to provide a waved bufling Wheel in which the buiiing or polishing surface is brought to any density desired in any width wheel and which will have a longer life than those presently in use.

Another object of the invention is to provide a buing wheel in which the waves `are uniformly carried through to the periphery of the wheel regardless of its width.

These and other objects are accomplished, in the preferred construction, by providing wave forming elements which have the shape of a sec'- tor of a predetermined thickness and placingthe bufling wheel sections between these sectors in a predetermined manner to form at least two diametrically opposite spaced apart dense col'- umns arranged radially about the axis of rota-f tion of the wheel. When the sections are pressed together by the lathe clamps which are used in mounting the assembled wheel on its spindle or shaft, the wave forming elements displace the bufng wheel sections from a single plane and compel them to form in two planes with the sides of the waves bridging and connecting the two planes.

For an understanding of the manner in which this invention is carried out and the waves formed in the bufng wheel, reference is to be had to the following description and the accompanying drawings in which:

Figure 1 is a plan view of the flexible spacer carrier having the same diameter as the lathe clamps with flexible wave forming elements for use between the lathe clamps and the wheel sections and inserted between the sections of the puffing wheels;

Figure 2 is a cross section through the vertical centreline of a pair of cooperating flexible carriers shown in Figure 1 in face to face relationship;

1 Claim. (C1. 51-193) Figure 3 is a vertical cross section through the centre of a modicationof the carrier with wave forming elements att-ached as shown in Figure l;

Figure 4 is a Vertical cross section through the centre of another modification ofthe carrier with wave forming elements attached as shown in Figure 1;

Figure 5 is a vertical cross section through the centre of still another modication of the carrier with wave forming elements attached as shown in Figure 1;

Figure 6 is a face view of a modication in which the wave forming elements are mounted on the buing wheel sections and used for placing wave forming elements between the lathe clamps .and the wheel sections, and also between the sections of the bung w'heel;

Figure 7 is a vertical cross section through the centre line of 'a pair of bung wheel sections with wave forming elements attached as shown in Figure 6;

Figure 8 is a vertical cross section of a modified form of wave forming elements attached to the bufng wheel section as shown in Figure 6;

Figure 9 is a vertical cross section of another arrangement of wave forming elements attached to the buing wheel section shown in Figure 6;

Figure 10 is a vertical cross section of still another arrangement of wave forming elements attached to thebuing Wheel section shown in Figure 6;

Figure l1 is a vertical cross section of another arrangement of the wave forming elements attached to Y,the bufing wheel section as shown in Figure 6;

Figure 12 is an enlarged cross section through the vertical lineof a luted bufling wheel to il lustrate theapplication of the dense columns to support the pressure of the lathe clamps, and combined with the wave forming and pressure elements to a butng wheel;

Figure 13 is a longitudinal cross sectional View taken on a vertical line through the centre of a completed waved buing wheel with both outside ends at and perpendicular to the axis of rotation of the wheel;

Figure 14 is a front view of the buling wheel shown in cross section in Figure 13;

Figure 15 is a longitudinal cross sectional View of a wide face fluted yleuning wheel with waves in the outside end sections; and

Figure 16 is a front view of the wheel shown in cross section in Figure 15.

In the drawings like letters of reference indicate corresponding parts in the different figures.

S represents a common buff section of any type made of material such as leather, felt, loose and stitched discs of cotton sheeting, and any other flexible material suitable for polishing and bufng.

R represents spacers of any flexible material such as canvas of various thicknesses commonly used between sections in a bullng wheel; usually the diameter of the lathe clamps, and not requiring either vent or lacing holes when used in a wheel not laced, such as shown in Fig. 1'2. When used in laced wheels the spacers R are formed with indentations and lacing holes as shown in Figs. 1 to 5 and in Figs. 13 to 16.

M represents lathe clamps, as shown in Figs. l2 to 16.

L represents lacing and lacing holes, as indicated in Figs. 1, 6, 13 and 15.

a represents a flexible carrier produced by attaching flute forming elements to spacers R as shown in Figs. 1-4 and used as desired to form the dense columns AD shown in Figs..l2 to 16.

b represents a flexible carrier made like carrier a, and used in dense columns at right angles to carrier a as indicated in the left hand side Fig. 2, and used as desired to form the dense columns BD in a wheel as shown in Figs. 12 to 16 f represents a ilexible carrier like carrier a, but with two pressure elements attached at right angles to two other similar pressure elements, as shown in Fig. 5, and used where desired, as shown in Figs. 12 to 16.

A represents a carrier which is formed by attaching the wave forming elements direct to a buff section, as shown in Figs. 6 to 9 and used where desired in forming the dense columns AD as shown in Figs. 12 to 16.

B represents a carrier made of a bui section, with wave forming elements attached like carrier A, and used at right angles to carrier A as shown on the left hand side in Figure 7 and used where desired as shown in Figs. l2 to 16. Both carrier A and carrier B are used synonymously with bufng section S, when the latter section has wave forming elements attached.

F represents a carrier made of a buff section like carrier A but with two pressure elements at right angles to two other pressure elements on the same side of the carrier as shown in Fig. 10 and used where desired as shown in Figs. l2 to 16.

K represents a carrier made of a buff section like carrier A, but with two pressure elements attached to one side, and on the reverse side two other similar pressure elements attached at right angles, as shown in Fig. 1l, and used where desired as shown in the enlarged Fig. l2 and Figs. 15 and 16.

AD and BD represent dense columns built up with the ilute forming elements on the carriers a, A, in the dense columns AD, and the wave forming elements on the carriers b, B, in the dense column BD, either with the wave forming elements between the lathe clamps and the wheel sections, as shown on the right hand end in Fig. 12, or on both ends as shown in Fig. 15, or with buff section separating the lathe clamps from the wave forming elements as shown on the left hand end in Fig. l2, or on both ends as shown in Fig. 13.

In its simplest form, this invention consists of sector shaped wave producing elements mounted on a circular carrier having the same diameter as the lathe clamps which are ordinarily employed to press the buil sections together. I prefer wave producing elements of two different thicknesses, marked d, c, and two of such elements being placed diametrically opposite each other as shown in Figs. 1 and 6. At least two carriers are required for use in forming a waved Wheel, oneat each end thereof. One carrier is rotated 90 with respect to the other carrier so that the carrier on the right hand end produces what I call two diametrically opposite dense columns AD, and the carrier on the left hand end produces two diametrically opposite dense columns BD located between the dense columns AD making four equally spaced dense columns of the same length arranged radially from centre of the buing wheel and. which support the pressure of the lathe clamps. The dense columns AD, under pressure of the lathe clamps, press the wheel sections to the left and against the lathe clamp on the left hand end of the wheel. The dense columns BD press the wheel sections to the right and against the lathe clamp on the right hand end of the Wheel. This forms what I term a balanced wheel, with perfect waves in the wheel sections, as shown in Figs.vl2 to 16.

The most desirable carriers have the wave producing elements attached to spacers R which may be of any desired thickness, from very thin to very thick, and to buff sections S used as carriers as shown in Figs. l, 2, 6 and '7. These gures show that the face of the wave producing elements are parallel with the face of the carriers and with the edges at right angles to the face.

In some cases it may be desirable to mount the wave producing elements on a rigid carrier or directly on the lathe clamps. Either construction places the wave producing elements between the lathe clamps and the wheel sections, in which position they give the same results as the spacer carriers and the section carriers. In such cases the carriers place the wave producing elements between the lathe clamps and the wheel sections, and develop waves on the outside ends and on both sides of the wheel. In a wide Wheel all such carriers must be associated with some form of the Wave producing or pressure elements or both, as shown in the detail drawings in Figs. 1 to 11.

The construction shown in Figs. l to 4 inclusive, consists of ilexible carriers a, b having the same diameter as the lathe clamps, and made by adding wave forming elements d, e to separators R, such as are commonly used between buf sections in a buing wheel. In Figs. 6 to 9 inclusive the carriers are made of buff sections hereinafter referred toas section carriers. The wave producing elements dev are mounted on each set of carriers in precisely the same position, namely the wave producing elements de on carrier b, Figs. 1, 2, and the wave producing elements de on carrier A are at right angles to the wave producing elements de on carrier B, Figs. 6, 7. In Figs. 2 and '7, I show these carriers with their wave producing elements in face to face relationship in order that their proper position may be shown.

When used in a hurling wheel, the carriers are separated by the wheel sections. It will thus be seen that the face of carriers aA are separated from the face of carriers bB by the thickness of the flute producing elements de when combined in a buing wheel. The elements de, under pressure of the lathe clamps, form a plurality of spaced apart dense columns, extending longitudinally and arranged in a circular pattern, about the axis of rotation. The dotted lines at the central portion from the top of ilute forming elements de on carriers a or A to the top of wave forming elements de on carriers b or B, show the depth and angles to the sides of the waves in the wheel sections between the lathe clamps. The dotted lines at the central portion Figs. 2 and '7 show the same formation and depth of waves.

All carriers in a waved wheel, except those on the ends, are pressed into two planes, the samer as working sections of the wheel.

I the wheel sections, and :the elements attached to said carriers become a -portion o-fthe ldense columns and are always inA theesame plane as the carriers in the dense columns, and therefore are parallel with the face of the lathe clamps, Athe same as the elements at the ends of the Wheel.

It is often preferable to ruse relativelythick and thin wave producing-elements in the same construction. Two nicdi-dcationsare illustrated in FigsjB, 4 and 8,` 9'. In Figs. 3- and 8 I show the'wave producing elements beingA made from the part e ofthe wave producing elements d@ in Figs. l, 2 and 6, 7 and attached to carriers al; and 13B` respectively. In Figs. 4- and 9 the wave producing elements` are made from the part d of the wave producing elements de in Figs. 1-, 2 and 6, 7. Y

i This combination of thick and thin wave producing elements gives a wide range forl making iluted wheels having both straight and iiuted sides, and with any depth of flutes desired inthe 'Il-he ilute producing elements d, as shown throughout these drawings represent one-half the thickness of the wave producing elements c.

It has been found that in a wide wheel, the effect of the wave producing elements at the ends of said wheel, the depth of the waves gradually get less toward the longitudinal center and finally disappear. This difficulty is overcome with a liberal use of-'wave producing elements and what I call pressure carriers, throughout the length o the VwheeLso that the fulll depth of waves is carried through the entire face or the wheel regardless of its width. An additional advantage is that the depth of waves may be lessened or increased when desired in any portion of the wheel. Each pressure carrier has foury pressure elements similar to the wave forininglelements previously described, positioned-909 apart about the axis of rotation to form pressure carriers f and F, Figs. 5 and l. The saine resultsl are obtained by taking cariers a,A, Figs. 4 and 9 and placing them face to face with carriers `ZL'B with the elements d positioned '909 apart.

Pressure carrier K, Fig. 11, is a modification of pressure carrier F, Fig. l0. In pressure carrier K, one' pair of diametrically opposite elements L are attached to one face of the carrier and the other pair of elements d are attached to the oppositefaee on the diameter which is perpendicular tothe diameter through the rst mentionedgpair. The same results are obtained by taking carrier A with elements d attached, as in Fig. 9 and placing it back to back with carrier B, with elements d positioned 90D from the wave producing elements d on carrier A. This construction is used usually in a waved wheel in which density is desired. Similar results are obtained with the use of spacer carriers ad, Fig. 4i, and placing carrier bd at right angle to it, with buif section between the two carriers ad, and bd. I call this construction, pressure carrier k, and it is applicable to where less density is desired in the wheel than given by pressure carrier K. All types of pressure carriers add the same thickness at the same time to the four dense columns, two dense columns AD and two dense columns BD. A desirable construction of the wave forming, elements is obtained with the combination of wave forming spacer carrier ad, Fig. 4, with the wave forming spacer, carrier ce, Fig. 3, by placing these two carriers with the elements 0f @@Qhalie on.. th?. 5.5m?. diiie? with buff section between said two spacer carriers ad and de forming the construction shown in part l, Fig. 12. A similar construction is made `with section carriers Ad, Fig. 9, with a pair of wave forming' elements e on the same diameter and on the reverse side ofsection carrier Ad. This construction with section carriers, gives greater density in a waved wheel, than the construction with spacer carriers. 'I'he enlarged Fig. 12 and Figs. 13 to 16 show various uses of the pressure elements and the wave producing elements and how these elements build up and form the aforesaid dense columns.

The spacer carriers and the section carriersare interchangeable, and. several are often` used, one superimposed on the otherwith buff sections between to get the depth of waves desired. The carriers, ll,y b and A, B are formed with lacing holes;` the dotted lines in Figs. 1- and 5 diagrammatically depicting the lacing. Note that the lacing holes are grouped in aV formation, the lacing cord forms two loops around the outer ends of the dense columns, which not only holds the wheel securely` together asa unit, but I have found that said formation is efhcient, tightens very rapidly and is quick-1y performed. Lacing holes for the dense columns AD are on the ver tical lines 5 5 andl forV the dense columns BD on the horizontal line 6 6; This places the dense columns A1390? from the dense columns BD in a clockwise orl anticlocltwise direction as shown inl Figs. 11 and' 6.

Referring to spacer carriers made of spacers Pv follan unlaced wheel, I= recommend-small holes in posi-tion of the lacing holes, onthe vertical line 5-5' asshownin Fig. 1-, tobe used for positioning the respective elements they carry, by threading a stringthrough saidholes, then draw itstraight out to indicate the position of` the elements, and when said elements are in proper position, withdraw the string before drawing the lathe clamps tight.

Fig. 6 shows V notches in the periphery of sectioncarrieriA- on the4 vertical'line 5 5, and at 9 therefromv are the VA notches on the horizontal-.line 6 8. These Vnotches indicate markings on thecarrier sections as means to assist, in, an unlaced wheel, in the positioning of the elements in thel densecolumns 11D for proper functioning.. with` the elementsl in the dense columns- BD. The rigid carriers andthe` spacer carriers are much alike, and I recommend that both typeshave markings to assist in positioning off theI elements on'` the righthand end for proper function with the elements on the left hand` end, as indicatedi'ior the spacer carriers, Figs. l: and 2.

Allcarriers from Figs. 1' toe andirom Fig-s. 6I to 9,- show-.twov elements diametricallyopposite each. other lon thersame carrienone on each side ofethe centre, andthe construction individually is'in balance. Itis obvious that a carrier made with one wave producing elementV in position on the centre line, as an individual carrier, would be out ofgbalance, but by placing two suchcarriers in a- Wheel, with the wave producing elements of each carrier on the same diameter but at op` posite ends of saiddiameter and on opposite endsotthewheel, said wheel would be in balance and have two dense columns, AD and BD,y of the same length, Supporting the pressure of the lathe clamps. Such awheel-built with the use of pressure elements, two pressure elements on the same diameter may,y be built with any width face desired;- W Y The mostidesirable construction is built' with two wave producing elements on each carrier. These produce four dense columns in a wheel, and they all must be built up to the same total length. It is clear that some of the wave producing elements may be widened and extended to the periphery of the working face of the wheel sections, such elements should be incorporated in a buff section, and become a part of the working portion of a section, but they in n way affect the wave producing functions of said elements.

Spacer carriers have long life, as they are in no way injured by the work performed by the wheel, and they are used repeatedly over and over again. The section carriers are limited to the life of the wheel sections. When rigid wave producing elements are mounted on rigid carriers or on the face of the lathe clamps, such carriers have indefinite length of life, but they are limited yto the construction that places the wave producing elements between the lathe clamps and the wheel sections, forming only a wheel with waves on the outside ends. However, they are used in combination with both the spacer carriers and the section carriers with flute producing and pressure elements attached, to control and insure the depth of waves throughout the width of a wide wheel.

Fig. 12 is an enlarged cross section view of a waved bufling wheel. The construction on the left hand end shows a buff section between the lathe clamp and the wave producing elements, forming the make up of a waved wheel with the outside ends running in one plane. On the right hand end, with the wave producing elements between the lathe clamp and the wheel sections, showing the make up of a fluted wheel with the outside ends waved. This construction brings out the dense columns AD formed by the wave producing and pressure elements in the vertical line on the right hand end, and dense column BD formed by the wave producing and pressure elements in the horizontal line on the left hand end. Note how the dense columns AD push all sections and intervening elements between the lathe clamps towards the lathe clamp on the left, forming two dense columns without any vacant places, and on the left the dense columns BD push all sections and intervening elements between the lathe clamps towards the lathe clamp on the right, forming dense column BD without any vacant places. In the drawing we see only dense column BD, as the top of the sections go straight out to the periphery.

Note the vacant places on the edges of the dense columns, through the entire central portion of the wheel between the dense columns under the lathe clamps, formed by the various pressure and wave producing elements that enter into the make up of the wheel. The vacant places formed by the various elements are in proportion to the thickness of the elements that make them.

It is obvious that the various wave forming and pressure elements sink partly into the wheel sections, which bulge up and absorb a portion of the vacant spaces they create, and the vacant spaces as shown in the drawings diagrammatically depict the vacancy and necessity of using the pressure carriers liberally.

The F and f type of pressure elements function as spacers, with no pressure on the sides of the iiutes in the wheel sections, while the K and lc type of pressure elements function as flute forming elements, as they cause the changing of the depth of waves in the carriers, but do not change the depth `of waves in the wheel sections. A11 of the pressure and wave forming elements have contact in the dense columns only, and the space between the dense columns has no contact and hence no pressure.

The four dense columns, two columns AD and two columns BD are all of the same length and support the pressure of the lathe clamps. Attention is called to the fact that waves generated by the columns AD envelop and fold over the various elements, and the same is true of the waves generated by the columns BD. This has the effect of locking the dense columns together in one position and the wheel cannot twist after the lathe clamps are drawn tight, which is a common difnculty in an ordinary bufling wheel.

The waved buing wheel shown in Fig. l2 is divided into ve parts, designated by the numerals I, 2, 3, 4 and 5, in which all the elements shown in Figs. 1 to 11 are employed, to illustrate the way they may be used to decrease or increase the depth of waves, or to maintain the depth of flutes unchanged, through the wheel, regardless of its width. Part I shows a buff section S between the lathe clamp and the wave producing elements, producing a waved wheel with the outside ends flat and running in one plane. The wave producing elements d immediately follow the buff section S next to the lathe clamp; then a second buff section S followed with the wave producing elements e which brings the waves to the full depth of the combined wave producing elements d and e, as shown by the waves in the third buff section S from the lathe clamp on the left hand end of the wheel. This is more fully brought out in Figs. 13 and 14. Part 2 shows construction with deep waves. Part 3 shows how the ute producing elements ad to the left, in the dense column AD, lessen the depth of waves in the sections and at the same time use the pressure carrier f as seen in each dense column. Part 4 again shows the flute producing carrier ad to the left, in dense columns AD and how it subtracts from the depth of waves. To the left in part 5, in dense column BD is flute producing carrier be, which immediately brings the depth of waves back to that shown under part 2. Then come the pressure carriers F and K which show clearly in dense columns, and on the right hand end of part 5 is the iiute producing carrier Ade, which places the wave producing elements de between the lathe clamp on the right hand end and the wheel sections| forming waves in the outside section of the wheel as brought out in Figs. 15 and 16.

Fig. 13 is a cross section illustrating a waved wheel with the end buiiing sections engaged between the lathe clamps and the iiute producing elements resulting in a wheel with straight ends and suitable for hand work. This wheel is made with the same wave producing elements and in the same order as shown in Figure l2 under part I. This produces a wheel of soft density. It is clear that if wave producing elements Ad, Fig. 9, and Ae, Fig. 8, were used leaving out the spacers R, and using pressure carrier K, Fig. 11, we would get a very dense wheel, entirely too hard for ordinary work. The range from very soft to very hard is great, but all involves the dense columns AD and BD which carry the pressure of the lathe clamps and permit all elements in the AD side of the wheel to perform their functions with the cooperating elements in the BD side of the wheel.

Fig. 14 is a front elevation of the finished iiuted wheel shown in the cross section in Fig. 13. The

iiutes in the working face of the various sections are affected by the several ilute producing and pressure elements as shown in said drawing. A laced wheel in one unit does not reduire any marking, as the lacing holes properly position the elements in the AD side for their function with the elements in the BD' side.

Figs. l and 16 illustrate another assembli7 of the wave forming elements and pressure carriers. This wheel is made in five distinct parts i, 2. il, il and 5, all running on one spindle as a single wheel. Part l has wave forming elements de between the lathe clamp and the wheel sections, no spaces between the sections S ex cept pressure carrier K which presses the carrier section at the elements d, two places on the AD side and two places on the 13D side. This part l makes an exceptionally hard wheel. Part 2 shows two pressure carriers F and single spacers R between the sections S, the waves are full depth as shown in part l. rlhis part 2 is moderately dense. Part 3 starts out with deducting elements ad from the depth oi the waves otherwise it is the same as part 2. Part 4 again starts out oy deducting elements ad from the depth of the waves and shows that the depth of the waves in part i is less than in part Si. Part l also includes apressure carrier 'f which adds to the length of the dense columns, the same as shown for the pressure carriers F in part 2. Part 5 starts out by adding the wave forming elements de and at once increases the depth oi the waves to the same as in parts I and 2, then at the end is the wave producing carrier Ade which places the wave producing elements de between the lathe clamp and the wheel section S the same as shown in Fig. 12 under 5. Also note the carrier f and two spacers R between the sections S. This is very soft but also effective because of the deep waves it carries. Both ends of this wheel (Fig. 15) have the wave producing elements between the lathe clamps and the wheel sections S which produce the waves on the outside ends of the wheel and suitable for automatic buiing machine work.

Parts i to 5 represent only a portion of the wide range of density in cutting quality possible in a wide wheel. Further it is clear that any one part may extend through the entire width of the wheel, and the waves in any portion of said wheel may be decreased or increased as desired for any special work required for said portion o a wheel. The depth oi waves aiect the cutting quality of a wheel entirely independent of the stitching in the sections. For easy handling and mounting of a wide face wheel on the latter spindle, I recommend the dividing of the wheel l0 into smaller units and the lacing of said units and in an unlaced wheel, tack the units together through the dense columns. All units are marked for assistance in assembling the several units in their respective position in a finished Wheel.

Fig. 16 shows the effect on the working face of the sections for the parts i to 5 as set up in the-cross section View Fig. I5. In part l there are no spaces except for the pressure elements K which press against the adjoining sections in four places, all other sections are tight together and part I is very dense. Part 2 with two pressure carriers F and single spacers between the sections, with the depth of waves the same as in part l. Part 2 is moderately hard. Part 3 is much like part 2 but a little softer. Part l is close to part 3 but again a little softer than part 3. Part 5 is soft and rapid working due to the deep waves and the wide spacers.

What I claim as new and desire to protect by Letters Patent of the United States is:

A bumng wheel comprising in combination a plurality oi exible bufrlng sections each having the general form of a centrally perforated normally at circular plate, a pair of complemental flexible fabric carriers for confining between them a group of said buiiing sections, each earrier having the general form of a centrally perforated normally flat disc and having a diameter substantially less than the said buiing sections, fabric 'wave forming elements mounted on each carrier and positioned so that the wave forming elements of one carrier register centrally in a circumferential direction 'between the wave forming elements of its complemental carrier, each wave forming element having the general form of a sector shaped flat member truncated towards the center of the carrier and being of the same predetermined thickness throughout, with means for pressing the bufng sections, the carriers and the wave forming elements mounted thereon together to form a builing wheel having a wave formation on the periphery of the bufng wheel.

HARRY ZIMMERMAN.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 1,912,069 Doermann May 30, 1933 2,109,905 Lippett Mar. 1, 1938 2,187,602 Hague Jan. 16, 1940 2,197,661 Hargy Apr. 16, 1940 2,244,582 Thompson June 3, 1941 2,274,185 Benbow Feb. 24, 1942 2,384,599 Case Sept. 11, 1945 2,522,092 Churchill Sept. 12, 1950 

